Conveyor belt cleaning systems are widely employed to remove adhered material from endless belts which among other things during the return flight of the belt can fall off and can create hazardous conditions. In addition to the hazardous conditions, particularly where sticky and clay-like materials are being conveyed, the adhered material may stay on the belt for extended periods and the accumulations thereof will reduce the efficiency of the conveyor belt operation. To overcome these problems, many devices have already been described, however these devices have either been too complex in construction or they could not satisfactorily cope with moist and clay-like materials. For example, U.S. Pat. No. 2,393,724 describes a belt cleaner, wherein scraper blades are yieldably kept in scraping contact with the belt by using a spring connected rigid lever to provide the desired tension. The tensioning spring is employed only on one side of the belt and consequently the tension exerted on the scrapers will not be uniform across the width of the area to be cleaned. In addition, the rigid lever only allows minor movement of the scrapers and due to this restriction, the scrapers will undergo rapid wear. Another system, shown in U.S. 2,398,821, attempts to overcome the non-uniform operation of the abovedescribed system by using spring tensioning devices on both sides of the belt. However, the rigid connecting levers employed in combination with the scrapers restrict the movement of the scrapers and excessive wear of the cleaning edges occurs. More recently, it was suggested in U.S. Pat. No. 3,101,831 to employ a wiper device for the removal of sticky materials from conveyor belts which adjusts itself in accordance with the load on the belt. The device described in this patent includes spring-biased levers pivoted to a belt frame and rollers to sense the tautness of the belt on its return flight. As the tautness of the belt changes, the rollers actuate the lever, which in turn influences the tension of the spring and thus can adjust the distance of the wiper from the belt. This device improves the operation of the above-described belt cleaning devices in that the spring tensioned levers allow a relatively yieldable movement of the wipers and thus reduced wear. Nevertheless, this device is only aimed at sensing the tautness of the belt during its carrying flight and the wipers will only be moved away from their position, when the tautness of the belt changes. Small quantities of sticky materials adhered to the belt on its return flight prevent the self-adjustment of the wipers and thus removal of material from the belt on its return flight will not be effectively achieved by this device.